1. Field of the Invention
The present invention relates to a technique for recording dots on the surface of a recording medium with the aid of a dot-recording head, and more particularly to a technique for printing images up to the edges of printing paper without soiling the platen.
2. Description of the Related Art
Printers in which ink is ejected from the nozzles of a print head have recently become popular as computer output devices. FIG. 24 is a side view depicting the periphery of a print head for a conventional printer. Printing paper P is supported on a platen 26o while facing the head 28o. The printing paper P is fed in the direction of arrow A by the upstream paper feed rollers 25p and 25q disposed upstream of the platen 26o and by the downstream paper peed rollers 25r and 25s disposed downstream of the platen 26o. Dots are recorded and images printed on the printing paper P when ink is ejected from the head.
When an attempt is made to print images without blank spaces up to the edges of printing paper with the aid of such a printer, it is necessary to arrange the printing paper such that the edges of the printing paper are disposed underneath the print head (that is, on the platen) and to cause ink droplets to be ejected from the print head when print data are specified for the areas that extend up to the edges of the printing paper and printing is carried out. With such printing, however, blank spaces form in the edge portions of the printing paper due to errors developing during the feeding of the printing paper, a shift in the impact location of the ink droplets, or the like. In addition, the ink droplets sometimes miss the edges of the printing paper (for which the droplets have been originally intended) and end up depositing on the platen due to errors developing during the feeding of the printing paper, a shift in the impact location of the ink droplets, or the like. In such cases, the ink deposited on the platen soils the printing paper transported over the platen in the next step.
It is an object of the present invention, which was perfected in order to overcome the above-described shortcomings of the prior art, to provide a technique that allows images to be printed up to the edges of printing paper while preventing ink droplets from depositing on the platen.
Perfected in order to at least partially overcome the above-described shortcomings, the present invention envisages performing specific procedures for a dot-recording device designed to record dots on the surface of a print medium with the aid of a dot-recording head provided with a plurality of dot-forming elements for ejecting ink droplets. This dot-recording device comprising a main scanning unit configured to drive the dot-recording head and/or the print medium to perform main scanning, a head driver configured to drive at least some of the dot-forming elements to form dots during the main scanning, a platen configured to extend in the main scanning direction and to be disposed opposite the dot-forming elements at least along part of a main scan path, a sub-scanning unit configured to move the print medium to perform sub-scanning in between the main scans, and a controller configured to control the dot-recording device.
The platen has a slot configured to extend in the main scanning direction, a width of the slot in the sub-scanning direction corresponding to a specific sub-scanning range on a surface of the dot recording head including at least part of the plurality of dot-forming elements.
In the printing, an expanded area is set in accordance with a type of print medium to be used in the dot recording, the expanded area extending lengthwise beyond at least front and rear edges of the print medium, and representing a recording area in which images are to be recorded on the print medium. Print data for recording images in the expanded area is prepared. Then edge printing is performed by ejecting ink droplets from at least some of the dot-forming elements disposed opposite the slot when images are printed at least in front- or rear-edge portions of the print medium on the basis of the print data.
With this arrangement, ink droplets can be prevented from depositing on the platen, and images can be printed without blank spaces up to the front and rear edge of the print medium. Selecting the correct size for the expanded area in accordance with the type of print medium makes it possible to prevent situations in which time is wasted when images are printed by ejecting ink droplets over an area that is unnecessarily wide for a given size of print medium.
The type of print medium preferably depends on dimensions of the print medium. When a print medium tilts away from its intended orientation, the extent to which the edge portions of the print medium are shifted increases with the dimensions of the print medium. Consequently, selecting an expanded area in accordance with a category related to the dimensions of the print medium makes it possible to establish the expanded area in an appropriate manner such that ink droplets are prevented from depositing on the platen, and images are printed without blank spaces up to the edges of the printing paper.
The type of print medium should preferably be set in accordance with the material of the print medium. The feed error occurring during the sub-scanning of a print medium sometimes varies with the type of print medium. Consequently, selecting an expanded area in accordance with a category related to the material of the print medium makes it possible to establish the expanded area in an appropriate manner such that ink droplets are prevented from depositing on the platen, and images are printed without blank spaces up to the edges of the printing paper.
The following procedure should preferably be adopted when ink droplets are ejected onto an expanded area. When ink droplets are ejected onto the front edge of the print medium, the position of the print medium in the sub-scanning direction is set such that the print medium is supported on the platen, the front edge of the print medium is brought to a point above the slot, and the front edge of the print medium reaches a point located in the sub-scanning direction upstream of a dot-forming element at a downstream end in the sub-scanning direction. When ink droplets are ejected onto the rear edge of the print medium, the position of the print medium in the sub-scanning direction is set such that the print medium is supported on the platen, the rear edge of the print medium is brought to a point above the slot, and the rear edge of the print medium reaches a point located in the sub-scanning direction downstream of a dot-forming element at an upstream end in the sub-scanning direction. With this arrangement, ink droplets can be prevented from depositing on the platen, and images can be printed without blank spaces up to the front and rear edge of the print medium.
The following procedure should preferably be adopted during the preparation of print data when the platen has a pair of lateral slots that are separated apart at a distance substantially equal to the width of the print medium, and the lateral slots extend in a sub-scanning range in which ink droplets are ejected from the plurality of dot-forming elements. The print data for recording images in an expanded area is prepared. The expanded area extends widthwise beyond left and right edges of the print medium but remaining between farthermost side walls of the pair of lateral slots. With this arrangement, it is possible to prepare print data whereby ink droplets can be prevented from depositing on the platen, and images can be printed without blank spaces up to the left and right edges of the print medium.
The following procedure should preferably be adopted when ink droplets are ejected onto the expanded area. The position of the print medium in the main scanning direction is set such that the print medium is supported on the platen, and the left and right edges of the print medium are brought to a point above the lateral slots. Dots are formed on the basis of image data representing an image extending outside the print medium beyond the left and right edges. With this arrangement, ink droplets can be prevented from depositing on the platen, and images can be printed without blank spaces up to the left and right edges of the print medium.
Print data should preferably be prepared such that these data contains information about recording condition of dots at pixels inside the expanded area. Such an embodiment makes it easier to set up portions of the expanded area beyond the edges of a print medium.
A dot-recording control device comprising a image data generator, an area size memory, an input unit, and a print data generator is provided as an embodiment of the present invention. The image data generator generates image data for the images recorded on the print medium. In the area size memory, information about an expanded area that extends in terms of length beyond at least the front and rear edge of the print medium and represents a recording area in which images are to be recorded on the print medium is stored for each type of print medium. The input unit is used to enter information about the types of print medium. In the print data generator, the print data for recording dots with which images can be formed in an expanded area are generated on the basis of information about the selected type of print medium, information about the expanded area, and image data.
This arrangement allows print data to be generated such that ink droplets can be prevented from depositing on the platen, and images can be printed without blank spaces up to the edges of the printing paper. Selecting the correct size for the expanded area in accordance with the type of print medium makes it possible to generate print data such that situations are prevented in which time is wasted when images are printed by ejecting ink droplets over an area that is unnecessarily wide for a given size of print medium.
The following procedure should preferably be adopted when the expanded area is divided, in order from the top, into an external front edge portion disposed in an area beyond the front edge of the print medium and configured such that formation of dots in this portion is assigned to the dot-forming elements disposed opposite the slot; an internal front edge portion on the front-edge portion of the print medium and configured such that formation of dots in this portion is assigned to the dot-forming elements disposed opposite the slot; an intermediate portion of the print medium; an internal rear edge portion on the rear-edge portion of the print medium and configured such that formation of dots in this portion is assigned to the dot-forming elements disposed opposite the slot; and an external rear edge portion disposed in an area beyond the rear edge of the print medium and configured such that formation of dots in this portion is assigned to the dot-forming elements disposed opposite the slot. Specifically, the area size memory substantially contains the dimensions of the external front edge portion in the sub-scanning direction, the dimensions of the internal front edge portion in the sub-scanning direction, the dimensions of the internal rear edge portion in the sub-scanning direction, and the dimensions of the external rear edge portion in the sub-scanning direction.
With this arrangement, the position of the expanded area in relation to the print medium can be defined in an appropriate manner. Ejecting ink droplets onto the external front edge portion, internal front edge portion, internal rear edge portion, and external rear edge portion of the expanded area makes it possible to print images on the edge portions of the print medium without forming blank spaces along the edges of the printing paper or depositing the ink droplets on the platen.
In the printing, following procedures are preferable. A specific print mode is selected from among a plurality of print modes. The print data for recording images in an expanded area is prepared. The expanded area extends lengthwise beyond the front and rear edges of the print medium in accordance with he selected print mode. Then ink droplets are ejected from at least some of the dot-forming elements disposed opposite the slot when images are printed in the front- and rear-edge portions of the print medium on the basis of the print data.
Such an embodiment allows expanded areas suited to individual print modes to be prepared and dots to be formed such that images are printed in an appropriate manner without blank spaces in the edge portions of the print medium.
When the plurality of print modes includes print modes with mutually different recording densities for the raster lines in the sub-scanning direction, a number of raster lines constituting the expanded area should preferably be established in accordance with the selected print mode when print data are prepared. With this arrangement, the size of the expanded area in the sub-scanning direction can be defined in accordance with the print mode by adopting the concept of xe2x80x9craster linexe2x80x9d for the printing device during actual printing.
Images should preferably be printed using solely the dot-forming elements disposed opposite the slot during printing in the front- and rear-edge portions of the print medium. Adopting this embodiment prevents the platen from being soiled when the front or rear edge shifts away from the slot during printing in the front- or rear-edge portion of the print medium.
The expanded area may be divided, in order from the top, into an external front edge portion, an intermediate portion, an internal front edge portion, an internal rear edge portion, an external rear edge portion. The external front edge portion is disposed in an area beyond the front edge of the print medium and configured such that formation of dots in this portion is assigned to the dot-forming elements disposed opposite the slot. The internal front edge portion corresponds to the front-edge portion of the print medium and is configured such that formation of dots in this portion is assigned to the dot-forming elements disposed opposite the slot. The intermediate portion corresponding to an intermediate portion of the print medium. The internal rear edge portion corresponds to the rear-edge portion of the print medium and is configured such that formation of dots in this portion is assigned to the dot-forming elements disposed opposite the slot. The external rear edge portion is disposed in an area beyond the rear edge of the print medium and is configured such that formation of dots in this portion is assigned to the dot-forming elements disposed opposite the slot.
It is preferable to set a number of raster lines for the external front edge portion according to the selected print mode such that dimensions of the external front edge portion remain the same in the sub-scanning direction with respect to different print modes having mutually different sub-scan resolutions, when the same type of print medium is used. It is also preferable to set a number of raster lines for the external rear edge portion such that the dimensions of the external rear edge portion remain the same in the sub-scanning direction with respect to different print modes having mutually different sub-scan resolutions, when the same type of print medium is used.
With this arrangement, the dimensions of the external front edge portion and external rear edge portion remain substantially the same in any print mode. For this reason, the expanded area can be established such that the likelihood of blank spaces forming in the edge portions of the print medium is reduced in a way that does not change with the print mode.
It is preferable to set a number of raster lines for the internal front edge portion such that the dimensions of the internal front edge portion remain the same in the sub-scanning direction with respect to different print modes having mutually different sub-scan resolutions, when the same type of print medium is used. It is also preferable to set a number of raster lines for the internal rear edge portion such that the dimensions of the internal rear edge portion remain the same in the sub-scanning direction with respect to different print modes having mutually different sub-scan resolutions, when the same type of print medium is used.
With this arrangement, the dimensions of the internal front edge portion and internal rear edge portion remain substantially the same in any print mode. For this reason, the expanded area can be established such that the likelihood of the platen being soiled is reduced in a way that does not change with the print mode.
When ink droplets are ejected onto the front edge of the print medium, the position of the print medium in the sub-scanning direction is preferably selected such that the print medium is supported on the platen, the front edge of the print medium is brought to a point above the slot, and the front edge of the print medium reaches a point located in the sub-scanning direction upstream of the dot-forming element at a downstream ende in the sub-scanning direction. When ink droplets are ejected onto the rear edge of the print medium, the position of the print medium in the sub-scanning direction is preferably selected such that the print medium is supported on the platen, the rear edge of the print medium is brought to a point above the slot, and the rear edge of the print medium reaches a point located in the sub-scanning direction downstream of a dot-forming element at an upstream end in the sub-scanning direction. With this arrangement, ink droplets can be prevented from depositing on the platen, and images can be printed without blank spaces up to the front and rear edge of the print medium.
In the case that the plurality of print modes include print modes having mutually different recording densities for the pixels in the main scanning direction, following embodiment is preferable. The dimensions of the expanded area is set such that the expanded area extends widthwise beyond left and right edges of the print medium but remains between farthermost side walls of the pair of lateral slots, and setting the number of pixels in the main scanning direction for the raster lines constituting the expanded area is specified substantially in accordance with the print mode thus selected. With this arrangement, it is possible to prepare print data whereby ink droplets can be prevented from depositing on the platen, and images can be printed without blank spaces up to the left and right edges of the print medium.
The position of the print medium in the sub-scanning direction is preferably set such that the print medium is supported on the platen, and the left and right edges of the print medium are brought to a point above the lateral slots. It is also preferable that dots are formed on the basis of image data representing an image extending outside the print medium beyond the left and right edges. With this arrangement, ink droplets can be prevented from depositing on the platen, and images can be printed without blank spaces up to the left and right edges of the print medium.
The present invention can also be implemented as a dot-recording control device for forming print data to be sent to a dot-recording unit for recording dots on the surface of a print medium with the aid of a dot-recording head provided with a plurality of dot-forming elements for ejecting ink droplets.
The print control device comprises a user interface unit, an expanded area memory, and a print data generator. The user interface unit displays a selection screen that allows the user to select one of a plurality of preinstalled print modes on a display, and that allows the selection be entered; wherein the area size memory comprises. The expanded area memory contains, for each print mode, a number of raster lines constituting the expanded area extending lengthwise beyond the front and rear edges of the print medium. The print data generator generates the print data for recording dots with which images can be formed in the expanded area on the basis of the selected print mode, the number of raster lines stored in the expanded area memory, and the image data for the images to be recorded on the print medium. Such an embodiment allows an expanded area suited to individual print modes to be prepared and images to be printed in an appropriate manner without blank spaces in the edge portions of the print medium.
The following printing procedure may preferably be adopted when a dot-recording device is used that is designed to record dots on the surface of a print medium with the aid of a dot-recording head provided with a plurality of dot-forming elements for ejecting ink droplets. The print medium contains a usable area which is defined by a closed perforated line in the entire area of the print medium. In the printing procedure, an expanded area for image recording is set in accordance with a type of print medium. The expanded area extends beyond the ends of the usable area along the entire perimeter thereof, and print data for recording images in the expanded area are prepared. Then dots are recorded by ejecting ink droplets from at least some of the dot-forming elements to the expanded area. With this arrangement, dots are printed without any margin being left up to the edges of the usable area, which is to be split off by perforated lines.
In the printing procedure, it is preferable that the print data is prepared in accordance with the selected printing mode selected from a plurality of printing modes. With this arrangement, an appropriate extended area for each printing mode can be prepared so that printing can be carried out appropriately without leaving any margins at the periphery of the usable area.
The present invention can be implemented as the following embodiments.
(1) A dot-recording method, dot-recording control method, print control method, or printing method.
(2) A dot-recording device, dot-recording control device, print control device, or printing device.
(3) A computer program for operating the device or implementing the method.
(4) A storage medium containing computer programs for operating the device or implementing the method.
(5) A data signal carried by a carrier wave and designed to contain a computer program for operating the device or implementing the method.
These and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with the accompanying drawings.